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K'NGSIEY 

ON  A NEW  LABRADOREAN  SPECIES  OF  ONCHIDI 
OPSIS,  A GENUS  OF  MOLLUSKS  NEW  TO  EAST- 
ERN NORTH  AMERICA;  WITH  REMARKS 
ON  ITS  RELATIONSHIPS 


BY 


FRANCIS  N.  BALCH 

Of  Boston,  Massachusetts 


No.  1761. — Frorp  the  Proceedings  of  the  United  States  National  Museum, 
Vol.  38,  pages  469-484,  with  Plates  21-22 

Published  October  6,  1910 


Washington 

Government  Printing  Office 


1910 


THE  UBRMW 
OF  TKfc 

ON  A NEW  LABRX0MMPfWSrPECIES  OF  ONCHIDI 
OPSIS,  A GENUS  OF  MOLLUSKS  NEW  TO  EAST- 
ERN NORTH  AMERICA;  WITH  REMARKS 
ON  ITS  RELATIONSHIPS 


BY 


FRANCIS  N.  BALCH 


Of  Boston,  Massachusetts 


No.  1761. — From  the  Proceedings  of  the  United  States  National  Museum, 
Vol.  38,  pages  469^484,  with  Plates  21-22 

Published  October  6,  1910 


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Washington 

Government  Printing  Office 


1910 


Digitized  by  the  Internet  Archive 
in  2017  with  funding  from 

University  of  Illinois  Urbana-Champaign  Alternates 


https://archive.org/details/onnewlabradoreanOObalc 


ON  A NEW  LABRADOREAN  SPECIES  OF  ONCHIDIOPSIS, 
A GENUS  OF  MOLLUSKS  NEW  TO  EASTERN  NORTH 
AMERICA;  WITH  REMARKS  ON  ITS  RELATIONSHIPS. 


By  Francis  N.  Balch, 


Of  Boston,  Massachusetts. 


During  the  summer  of  1908  Mr.  Owen  Bryant,  cruising  on  the  Labra- 
dor coast,  made  opportunity  for  some  dredgings  in  moderate  depths. 
The  resulting  mollusks,  with  the  exception  of  the  Nudibranchs,  were 
placed  in  the  hands  of  Mr.  C.  W.  Johnson,  curator  of  the  Boston 
Society  of  Natural  History.  The  small  collection  of  Nudibranchs 
was  intrusted  to  me.  In  it  was  included  an  apparently  naked  mol- 
lusk,  which  Mr.  Bryant  took  for  a dorid  form,  but  which  is  in  fact 
a fine  new  species  of  the  internal-shelled  genus  Onchidiopsis  belong- 
ing to  the  family  Lamellariidse.  Mr.  Bryant’s  mistake  was  far  from 
unnatural,  and  it  is  possibly  owing  to  similar  errors  on  the  part  of 
other  collectors  that  we  owe  almost  all  our  knowledge  of  the  group 
to  specialists  on  the  Opisthobranchiata  (especially  the  Nudibranchs), 
as  will  appear  from  the  literature  cited  at  the  end  of  this  paper. 

The  specimen  is  a fine  adult,  well  preserved  in  formol,  and  is  of 
interest  from  several  points  of  view — first,  from  the  point  of  view 
of  geographical  distribution,  the  genus  being  previously  unknown 
from  eastern  America,  though  present  in  Greenland  and  Alaska;  sec- 
ond, from  the  point  of  view  of  systematic  morphology,  the  genus 
being  probably  the  last  term  of  an  extraordinary  aberrant  series 
and  containing  few,  perhaps  only  one,  hitherto  known  species;  third, 
from  the  point  of  view  of  teratology,  since  the  specimen  has  a bifid 
left  tentacle  the  abnormal  member  of  which  bears  what  appears  exter- 
nally to  be  an  extra  eye  resembling  the  normal,  but  proves  on  section- 
ing to  be  a group  of  four  eyes  apparently  proliferating  one  from  the 
other,  in  various  stages,  making  a case  quite  unique  so  far  as  the 
records  show. 

The  present  paper  contains  a description  of  the  specimen,  with  a 
brief  discussion  from  the  first  and  second  points  of  view.  The  tera- 
tological  aspect  was  presented  in  a separate  paper  read  before  the 
American  Society  of  Zoologists  (Eastern  Branch)  during  convocation 
week  in  Boston,  December,  1909,  and  which,  it  is  expected,  will  be 
published  in  the  American  Naturalist. 

Out  of  a desire  not  to  mutilate  the  single  specimen  more  than 
necessary,  examination  has  been  confined  to  external  points  and  to  the 


Proceedings  U.  S.  National  Museum.  Vol.  38— No.  1761 


469 





470 


PROCEEDINGS  OF  THE  NATIONAL  MUSEUM. 


VOL.  38. 


internal  shell,  the  radula  and  pharyngeal  bulb,  the  features  of  the  gill- 
cavity,  and  the  anatomy  and  histology  of  the  bifid  left  tentacle.  The 
material,  consisting  of  the  partially  dissected  body  in  formol,  the 
shell  in  formol,  and  a mount  of  the  radula,  has  been  deposited  in 
the  U.  S.  National  Museum. 

The  description  follows: 

ONCHIDIOPSIS  CORYS,o  new  species. 

Locality. — Single  specimen  dredged  off  Fish  Island,  outside  Hebron 
Harbor,  Labrador,  in  75  fathoms,  mud,  August  26,  1908. 

Size. — In  formol : Length,  20  mm. ; breadth,  16  mm. ; height,  14  mm. 

Color.— In  life:  Cream  colored,  with  8(?)  spots  of  varying  shades 
of  brown  [Bryant's  notes].  In  formol:  Notaeum,  ground-color  light 
purplish  brown  with  darker  markings  on  the  lower  sides,  faintly  and 
vaguely  reticulated  over  the  top  and  upper  sides,  so  as  to  give  the 
effect  of  about  twelve  ill-defined  blotches  of  the  ground  color.  Ante- 
rior lobes  lighter  and  more  yellowish.  Head  and  foot  same  as  ground 
color  of  notaeum.  Eye  spots  black. 

General  form. — (PI.  21,  figs.  1,  2,  3.)  The  notaeum,  smooth  on  top 
and  sides,  wrinkled  or  strongly  folded  and  vesiculate  elsewhere,  rises 
in  a backward-tilted  dome,  suggesting  a Grecian  helmet  (whence  the 
name  chosen),  the  curiously  puffed  and  wrinkled  anterior  border  pro- 
jecting visor-fashion.  The  top  and  sides  of  the  notaeum  are  closely 
applied  to  the  thin  internal  shell,  which  in  turn  closely  covers  the 
large  dome-shaped  visceral  hump.  Below  the  folded  border  of  the 
notaeum  are  seen  the  well-demarked  head  and  the  foot,  the  former 
bearing  a large  proboscis  of  truncated-cone  shape,  and  two  thick 
tentacles  about  as  long  as  the  proboscis,  with  conspicuous  eye  spots 
about  two-thirds  way  up  from  their  bases.  The  foot  in  the  preserved 
specimen  is  of  moderate  size,  reaching  anteriorly  only  to  the  level  of 
the  tentacles  and  posteriorly  projecting  about  one-sixth  of  its  length 
beyond  the  border  of  the  notaeum,  the  projecting  portion  sharply 
upturned.  The  very  large  penis,  situated  on  the  right  side  of  the  neck, 
comes  partially  into  view  below  the  notaeum  above  the  right  tentacle. 

Notaeum. — Smooth  to  the  naked  eye  (actually  finely  wrinkled),  thin, 
and  closely  investing  the  thin  internal  shell  on  the  top  and  sides ; the 
lower  sides  more  wrinkled;  the  border  thickened,  strongly  folded, 
and  vesiculate  or  puffy;  the  anterior  border  quite  specialized,  being 
very  strongly  folded,  and  vesiculate  or  pustulate,  so  as  to  present  the 
appearance  of  a mass  of  crowded  water  blisters.  This  anterior  lappet 
projects  like  a visor  or  eye  shade  over  the  head  and  is  cut  by  the  deep 
inspiratory  cleft  (lying  just  to  the  left  of  the  median  line)  and  the 
less  deep  expiratory  cleft  (lying  about  65  degrees  to  the  right,  and 
rather  a fold  than  a cleft)  into  a well-demarked  right  and  a much  less 
well-marked  left  lobe.  In  life  these  anterior  lobes  or  lappets  evi- 
dently play  an  important  part,  as  they  are  large,  muscular,  and 


a Kopuc,  signifying  an  homeric  helmet. 


NO.  176-1. 


A NEW  SPECIES  OF  ONCHIDIOPSIS—BALCH. 


471 


highly  specialized.  Probably  they  are  concerned  in  respiration  and 
also  furnish  an  extensible,  thick,  and  soft  sort  of  cushioned  armor  for 
the  head,  which  lacks  the  ordinary  defense  of  withdrawal  under  a shell. 

Shell. — (PL  21,  figs.  4,  5,  6.)  On  cutting  open  the  notaeum  the  shell 
appears  as  a quite  transparent  whitish  film  closely  applied  like  a cap 
to  the  top  and  front  of  the  solid  dome  of  the  visceral  hump.  Not  being 
adherent  either  to  the  notaeum  or  to  the  true  mantle  (which  lies  below 
it  as  a transparent  membrane  investing  the  visceral  hump)  it  can  be 
simply  lifted  out  with  forceps.  It  has  about  the  appearance  and  con- 
sistency of  a film  of  collodion.  It  is  not  stiff  enough  to  resist  the  action 
of  gravity  in  air,  but  has  sufficient  elasticity  to  regain  its  form  when 
restored  to  a liquid  medium.  It  is  smooth  except  for  rather  faint 
concentrjc  lines  of  growth.  In  general  shape  it  may  be  roughly 
likened  to  a very  highly  arched  finger-nail.  A peculiar  and  instruc- 
tive feature  is  the  infolding  of  the  posterior-inferior  portion  into  the 
posterior-superior  portion.  A comparison  of  PI.  21,  figs.  7,  8,  and  9, 
will  make  clear  what  has  happened.  Figs.  7 and  8 are  rough  rep- 
resentations of  the  shells  of  Marsenina  prodita  (Loven)  and  M. 
ampla  (Verrill),  respectively.  The  former  is  lymnoid.  The  latter 
is  more  degenerate  and  consists  of  only  one  whorl,  mostly  mouth. 
Fig.  9 is  a diagrammatic  sketch  of  our  shell  represented  as  a solid 
object.  The  homology  of  the  infolded  portion  is  plain.  The  last 
whorl,  becoming  degenerate  to  the  point  of  abandonment  and 
reduced  to  a mere  posterior  wall  of  the  mouth  space,  has  simply 
collapsed  into  the  spire  cavity.  This  is  not,  however,  a mere  acci- 
dental collapse,  as  wet  paper  might  collapse  upon  itself.  It  is  struc- 
tural and  permanent.  The  infold,  if  straightened  out,  springs 
smartly  back  again  and  the  line  of  folding  is  clearly  marked  struc- 
turally. The  cavity  of  the  last  whorl  (i.  e.,  the  space  between  the 
infold  and  the  top  of  the  shell)  has  been  abandoned  by  the  animal  and 
practically  obliterated.  In  this  and  other  obvious  respects  the 
infold  materially  differs  from  the  1 ‘deck”  or  “shelf”  of  Crepidula, 
with  which,  however,  it  is  somewhat  parallel.  In  the  other  species 
of  Onchidiopsis  there  is  no  such  structure,  so  that  in  this  respect  the 
present  species  serves  to  connect  the  genus  as  hitherto  known  with 
more  normal  forms  and  offers  an  instructive  study  in  the  degenera- 
tion of  shell  armor.  The  shell  in  the  present  species  differs  from  those 
hitherto  described  in  presenting  neither  lateral  emargination  nor  wing. 

Visceral  hump. — Next  below  the  thin  membranous  true  mantle 
already  mentioned  lies  the  solid  smooth  dome  of  the  visceral  mass, 
purplish-yellow  in  color,  the  visible  portion  chiefly  consisting  of  the 
glands  of  the  genital  system.  It  is  larger  than  the  shell,  which  only 
partially  covers  it,  but  the  discrepancy  is  not  so  great  as  in  the  other 
species  of  the  genus,  where  the  shell  is  little  more  than  a scale  over  the 
gill-cavity  region,  while  here  the  whole  top  and  sides  of  the  visceral 
hump  are  covered.  In  the  gill-cavity  region  the  black  base  of  the  large 
osphradium  showing  through  the  roof  of  the  cavity  is  conspicuous. 


472 


PROCEEDINGS  OF  THE  NATIONAL  MV  SEEM. 


VOL.  38. 


Gill  cavity  and  branchial  complex. — The  large  thin-roofed  branchial 
cavity  opens  by  a long  and  narrow  crescentic  horizontal  slit  just 
above  the  nuchal  fold.  On  opening  it  the  most  conspicuous  object 
is  the  osphradium  running  diagonally  across  the  left  side  of  the  roof 
and  consisting  of  a double  series  of  leaflets  (PI.  21,  fig.  10)  set  on 
either  side  of  a central  rhachis  after  the  usual  fashion,  but  very  large 
and  having  the  side  edges  and  basal  edges  of  the  leaflets  black.  It 
differs  markedly  in  the  shape  of  the  leaflets  (which  are  distinctly 
bilobed)  from  the  other  species  of  the  genus.  Beside  it,  on  the  right, 
the  gill,  though  larger,  is  much  less  conspicuous.  Its  thin  leaflets, 
colored  like  the  neighboring  tissue,  arranged  in  a single  row  on  the 
right  of  the  rhachis,  are  long  and  narrow  compared  with  those  of 
the  other  species  of  the  genus,  and  simply  pointed.  The  anus  was 
not  satisfactorily  made  out,  the  right-hand  part  of  the  roof  of  the 
gill  cavity  (where  it  doubtless  lies,  as  in  the  other  species)  having 
been  disturbed  in  the  examination  of  other  parts. 

Genital  system. — This  was  only  examined  externally,  but  nothing 
appears  to  cast  doubt  on  its  substantial  conformity  with  the  other 
species  of  the  genus.  The  female  genital  opening  was  not  satis- 
factorily made  out,  the  region  near  the  anus  where  it  should  occur 
having  been  disturbed,  as  above  stated.  The  penis  (PI.  22,  fig.  1)  is 
extremely  large  (quite  double,  in  proportion,  that  figured  or  described 
for  the  other  species)  and  otherwise  peculiar.  Arising  from  the  nuchal 
fold,  on  the  right  side  of  the  neck,  above  and  just  to  the  left  of  the 
base  of  the  right  tentacle,  is  a massive  base  as  thick  as  the  base  of  the 
tentacle  itself  and  half  again  as  long  as  broad,  directed,  backward 
and  slightly  outward  and  upward.  Sharply  turning  more  than  a 
right  angle  (so  that  it  runs  forward,  and  slightly  outward  and  down- 
ward) the  organ  now  rapidly  diminishes  in  size  to  a slender  neck  of 
less  than  a quarter  the  original  diameter.  The  minimum  size  is, 
however,  scarcely  reached  before  the  organ  suddenly  swells  again 
(though  this  time  only  slightly)  at  the  same  time  acquiring  along  its 
external  margin  a great  crest  recalling  in  form  and  proportion  the 
conventional  mane  of  the  chess  knight.  The  crest  rapidly  diminishes 
and  at  the  point  where  it  is  lost  the  organ  suddenly  bends  directly 
back  upon  itself,  at  the  same  time  diminishing  to  a point  which 
reaches  back  to  the  level  where  the  crest  began.  A fair  idea  of  the 
relations  of  the  parts  can  be  given  by  comparing  the  whole  structure 
to  an  arm,  the  upper  arm  enormously  fat,  the  forearm  starting  fat 
but  rapidly  dwindling  to  a thin  wrist,  the  hand  and  fingers  very  long, 
and  the  back  of  the  hand  expanded  into  a high  crest.  In  attitude 
the  arm  must  be  strongly  flexed  and  the  fingers  pressed  together  at 
the  tips  and  impossibly  flexed  so  as  nearly  to  touch  the  inside  of  the 
wrist.  The  finer  structure  was  not  examined.  Bergh  has  minutely 
described  it  for  the  related  species. 

Head. — The  broadly  ovoid  body  mass  is  bounded  in  front  by  a 
strong  nuchal  fold  clearly  marking  the  transition  to  the  head  region, 


no.  1761. 


A NEW  SPECIES  OF  ONCHIDIOPSIS—BALCH. 


473 


which  widens  again  beyond  it.  The  region  is  about  twice  as  broad 
as  long  and  is  prolonged  at  its  anterior  corners  into  the  tentacles, 
while  from  its  anterior  face  springs  the  snout  or  rostrum. 

Tentacles  and  eyes. — (PI.  22,  fig.  1.)  The  tentacles  are  thick,  fleshy, 
and  moderately  wrinkled,  ending  in  an  abrupt  taper.  In  life  they  are 
doubtless  somewhat  longer  and  thinner,  but  the  contraction  in  this 
specimen  does  not  appear  to  have  been  extreme.  They  curve  gently 
outward  and  upward.  Each  bears  on  its  external  (and  slightly  supe- 
rior) surface  a large  black  eye  spot,  which  appears  as  a lump  under  the 
skin,  raising  the  latter  into  a slight  prominence  out  of  which  the  eye 
looks  forward  along  the  tentacle.  In  effect  the  eye  is  set  in  the  an- 
terior face  of  a very  rudimentary  peduncle  or  ophthalmophore  re- 
sembling a bracket.  On  sectioning,  the  eyes  are  seen  to  present  no 
special  features,  but  are  well  developed  and  evidently  highly  func- 
tional. There  is  no  appearance  of  any  corneal  modification  of  the 
skin  except  a slight  thinning.  The  retina  is  heavily  pigmented ; the 
lens  large,  filling  nearly  the  whole  eye  cavity.  The  left  tentacle  in 
this  specimen  bore  an  appendage  branching  off  from  its  base  and 
pointing  posteriorly  along  the  left  side  of  the  neck,  nearly  as  long  as 
the  tentacle  itself  but  less  than  half  as  thick.  This  appendage  bore 
on  its  exterior  face  an  extra  eye,  or  rather,  as  heretofore  mentioned, 
a cluster  of  four  extra  eyes  apparently  in  various  stages  of  prolifera- 
tion one  from  another.  Undoubtedly  the  whole  structure  (neglect- 
ing the  feature  of  the  apparent  proliferation  of  eyes  in  the  extra 
eye  spot)  is  to  be  interpreted  as  a case  of  bifid  left  tentacle  somewhat 
masked  by  the  turning  backward  of  the  external  member  and  its 
reduction  in  size  and  change  in  proportions.  If  this  member  were 
turned  forward  and  thickened  and  curved  like  the  normal  tentacle, 
it  and  its  eye  spot  would  bear  the  relation  of  a mirror  image  to  the 
normal  tentacle  and  its  eye  spot,  as  is  commonly  the  case  with  similar 
bifid  structures.® 

Rostrum  and  mouth. — (PI.  22,  figs.  1,  2,  3.)  From  the  anterior  face 
of  the  head  region,  and  from  under  a fold  of  skin  connecting  the  bases 
of  the  tentacles,  springs  the  thick  and  heavy  rostrum  in  the  shape  of 
a truncated  cone  about  once  and  a half  as  long  as  broad.  It  is  only 
moderately  wrinkled  and,  like  the  tentacles,  is  in  life  probably  some- 
what but  not  greatly  more  protrusible.  It  may  probably  be  also  some- 
what more  contractible  but  not  greatly.  The  thick  and  heavy  skin 
and  the  rather  slight  musculature  which  appear  on  dissection  do  not 
point  to  an  extremely  elastic  or  contractile  organ.  Its  anterior  end 
forms  aflat  face  of  oval  form,  the  major  axis  dorso-ventral.  In  this 
axis  the  mouth  appears  as  a simple  slit  two-thirds  the  length  of  the 
oval,  with  wrinkled  lips.  Unless  the  rostrum  is  much  more  change- 
able in  form  than  above  supposed  it  differs  markedly  from  the  other 
species  of  the  genus,  where  it  is  bulbous.  Doubtless  the  pharyngeal 


, a See  cases  collected  in  Bateson  [1894]. 


474 


PROCEEDINGS  OF  THE  NATIONAL  MUSEUM. 


vol.  38. 


bulb  can  be  pushed  forward,  but  even  this  could  hardly  produce  such 
forms  as  figured  by  Bergh. 

Jaws. — (PL  22,  figs.  2,  3,  4.)  The  mouth  opens  into  a narrow  tube 
of  oval  section,  thin  walled,  and  running  between  the  two  jaws  which 
arch  it  over  and  also  partly  inclose  its  sides.  The  jaws  are  of  brown 
chitin,  thin  and  delicate,  about  twice  as  long  as  high,  serrate  on  their 
lower  edges,  the  serrations  growing  coarser  from  posterior  to  anterior. 
Each  jaw  is  molded  to  fit  along  the  top  and  one  side  of  the  mouth 
tube,  narrows  to  a rounded  point  posteriorly  and  appears  to  be  squarelv 
and  smoothly  cut  off  anteriorly;  but  about  this  last  there  may  be  some 
doubt  since  there  is  a suspicion  that  in  removing  these  delicate  objects 
from  the  tough  mouth  gristles,  serrations  or  other  structures  at  the 
point  of  attachment  may  have  been  broken  off  and  lost.  To  the 
powers  of  the  dissecting  microscope  the  jaws  appear  covered  with 
beautifully  regular  minute  transverse  (i.  e.,  dorso-ventral)  striations 
corresponding  in  spacing  with  the  serrations  of  the  ventral  edge. 
The  real  microscopic  structure  was  not  studied.  There  can  be  little 
doubt  it  is  substantially  that  several  times  figured  by  Bergh  for  simi- 
lar objects,  i.  e.,  a sort  of  mosaic  of  minute  chitinous  bars  locked 
together  in  a diamond  pattern  which  gives  the  impression  of  trans- 
verse (i.  e.,  dorso-ventral)  lines,  the  longitudinal  (i.  e.,  antero-pos- 
terior)  lines  being  broken  in  the  pattern. 

Pharyngeal  bulb  and  radula. — (PI.  22,  figs.  2,  3,  5,  6.)  Near  the  pos- 
terior end  of  the  jaws  the  thin-walled  mouth  tube  suddenly  swells  to 
more  than  twice  its  former  diameter  to  contain  the  large  muscular 
pharyngeal  bulb.  The  structure  of  this  was  not  minutely  studied  as 
it  offered  no  prospect  of  material  difference  from  the  similar  organs  so 
often  and  fully  elucidated  by  Bergh  Its  form  sufficiently  appears  from 
the  figures  and  must  in  life  vary  greatly  in  the  course  of  the  complicated 
motions  of  the  radula  which  latter,  however,  in  this  species  I think  is 
almost  certainly  not  protrusible.  I think  so,  both  because  the  mouth 
and  end  of  the  snout  are  too  small  and  because  there  is  a pretty  clear 
mutual  adjustment  of  the  radula  and  jaws  to  trituration  of  the  food 
between  them  in  the  swollen  portion  of  the  mouth  tube.  The  radula 
commences  posteriorly  in  a bulb  borne  on  a long  stem  which  is  a pro- 
longation of  the  posterior  base  of  the  pharyngeal  bulb  but  rises  sharply 
upward  and  to  the  left,  penetrates  the  dorsal  wall  of  the  mouth 
tube,  then  curls  over  forward  and  outward  and  lies  on  top  of  the 
mouth  tube  at  its  widest  part  to  the  left  of  its  center.  The  radula, 
starting  in  this  bulb,  passes  down  through  its  stem  and  so  into  the 
lower  posterior  part  of  the  pharyngeal  bulb,  through  which  it  then 
turns  sharply  upward,  reaching  its  surface  (and  so  coming  into  use  in 
the  open  mouth-cavity)  at  the  highest  point  of  the  bulb’s  top.  At 
the  same  point  the  radula  attains  its  own  greatest  width,  for  by  wear- 
ing off  of  the  lateral  members  and  by  appression  it  thence  slightly 
narrows  as  it  runs  forward  down  the  anterior  slope  of  the  pharyngeal 


no.  1761. 


A NEW  SPECIES  OF  ONCIIIDIOPSIS—BALC II . 


475 


bulb,  ending  abruptly  shortly  after  passing  within  the  jaws.  It 
attains  a length  of  60  transverse  rows  and  is  typically  taenioglossate, 
having  the  usual  formula  2-1 -1-1 -2.  The  median  or  rhachidian 
tooth  consists  of  a base  about  as  wide  as  high,  with  slightly  convex 
lower  edge  and  concave  sides,  the  top  of  which  curls  over  backward 
to  form  the  dentate  functional  blade.  The  latter  bears  a large  central 
cusp,  long  and  pointed,  flanked  by  very  irregular  and  much  smaller 
denticulations,  about  eight  on  each  side  but  varying  from  six  to  ten 
and  showing  a distinct  tendency  to  alternation  of  larger  and  smaller. 
The  whole  tooth  is  arched,  with  the  convexity  posterior,  so  that  the 
functional  upper  portion  as  seen  from  on  top  has  a roughly  crescentic 
form.  The  laterals,  or  ad-medians,  are  on  the  same  general  plan,  but 
the  basal  portion  is  much  narrower  and  higher,  the  central  (or  sub- 
central) cusp  longer  in  proportion  and  flanked  by  about  seven  denticu- 
lations on  the  external  and  five  on  the  internal  side.  They  are  set  on 
the  basal  membrane  at  an  angle  with  the  rhachis,  so  that  the  central 
cusps  point  slightly  inward.  The  uncini  have  the  form  of  simple 
smooth  arched  claws,  curving  upward,  backward,  and  slightly  out- 
ward. By  folding  inward  over  the  admedians  they  can  be  laid  flat. 
Possibly  they  can  also  be  folded  outward.  The  radula  presents  only 
minute  differences  from  the  other  species  of  the  genus  so  far  as 
comparison  with  figures  shows. 

Foot. — (PI.  21,  figs.  2,  3;  PI.  22,  fig.  1.)  Moderate  in  size,  as  before 
described,  anteriorly  slightly  bowed  and  concave,  posteriorly  obtusely 
pointed.  The  anterior  angles  form  distinct  stout  lobes  or  auricles. 
The  posterior  portion,  projecting  beyond  the  notseum  border,  is  some- 
what specialized,  being  slightly  broader  and  thicker  than  at  the  point 
where  it  passes  beneath  the  notseum,  and  curled  sharply  upward.  This 
might  be  thought  to  be  a mere  accident  of  preservation  in  this  speci- 
men, but  has  been  described  for  other  species  of  the  genus.  Whether 
it  occurs  in  life  or  is  due  to  the  strong  contraction  in  death  of  the 
structure  next  mentioned  is  uncertain.  The  dorsal  surface  of  the 
foot  is  appressed  to  the  edge  of  the  notseum  where  it  passes  beneath 
it,  and  at  and  posterior  to  this  point  bears  a narrow  central  muscular 
thickening  or  pad.  Similar  structures  have  been  minutely  described 
by  Bergh  for  other  species  of  the  genus.  The  function  is  unknown 
but  does  not  its  position  suggest  that  it  may  be  merely  a vestigial 
operculiferous  lobe '? 

Parasites. — On  sectioning  the  left  tentacle  two  large  encysted 
parasites  were  found,  complex  organisms,  probably  Trematodes. 
Prof.  Henry  B.  Ward,  of  the  University  of  Illinois,  is  kindly  examin- 
ing them  and  it  is  hoped  to  present  further  conclusions  in  connection 
with  the  forthcoming  paper  in  the  American  Naturalist.  The  highly 
abnormal  character  of  this  tentacle  and  its  parasitization  may  possi- 
bly be  more  than  a coincidence.  Nematodes  have  been  found  with 
the  larvae  of  0.  grcenlandica  (Bergh  [1887],  p.  276,  note). 


476 


PROCEEDINGS  OF  THE  NATIONAL  MUSEUM. 


vol.  38. 


RELATIONSHIP  OF  THE  PRESENT  SPECIES  TO  THE  OTHER  SPECIES 

OF  THE  GENUS. 

The  names  applied  to  species  now  considered  to  belong  to  Onchidiop- 
sis  are  few,  being  in  chronological  order  as  follows: 

Coriocella  carnea  Kroyer  [1847],  p.  115,  no.  10. 

Coriocella  recondita  Kroyer  [1847],  p.  115,  no.  11. 

Lamellaria  glaciolis  M.  Sars  [1850],  p.  185. 

Onchidiopsis  gramlandica  Bergh  [1853],  p.  346. 

Onchidiopsis  reinhardi  Beck.  Morch  [1868],  p.  25. 

Onchidiopsis  grcenlandica,  var.  pacifica  Bergh  [1887],  p.  278. 

Onchidiopsis  palliata  Loven  (unpublished,  a label  name,  teste  Pos- 
selt  [1898.]). 

Of  these  recondita  is  the  young  of  carnea;  palliata  and  reinhardi 
were  both  applied  to  unusually  large  specimens  of  grcenlandica  ( rein- 
hardi said  to  be  over  three  inches  long) ; and  carnea  itself  is  now 
treated  as  a full  synonym  of  grcenlandica. a 

This  leaves  only  glaciolis  Sars,  and  grcenlandica  Bergh  with  its  var. 
pacifica  Bergh.  The  real  status  of  these  forms  is  in  the  highest  degree 
problematical.  All  are  strictly  boreal,  and  Bergh  is  the  great  author- 
ity on  them.  Unfortunately  his  last  publication  on  the  group — in 
his  great  monograph  of  the  Marseniadse  (Bergh  [1887]) — while  very 
full  and  elaborate,  does  not  do  its  author  justice.  The  text  and  plates 
are  repeatedly  in  disagreement,  and  the  former  has  been  found  blind 
by  others  besides  the  present  writer.  Among  other  things,  both 
description  and  figures  appear  to  show  that  grcenlandica , var.  pacifica 
is  in  reality  nearer  to  glaciolis  than  it  is  to  grcenlandica,  being  a variant 
in  the  same  direction  as  glaciolis  but  more  extreme.  But  Bergh  him- 
self evidently  felt  great  doubt  whether  he  was  in  fact  dealing  with 
more  than  one  species  in  all.  With  the  growth  of  his  work  on  the 
genus,  and  the  accumulation  of  more  material,  his  species,  at  first 
fairly  well  distinguished,  have  approached  each  other  more  and  more, 
till  he  finally  relies  for  the  discrimination  of  grcenlandica  from  glaciolis 
on  the  fact  that  in  the  former  the  shell  is  broader  behind,  the  osphra- 
dium  black  on  its  base,  the  gill  leaflets  of  “ somewhat  peculiar  form,” 
and  the  inner  members  of  the  pairs  of  uncinal  hooks  not  denticulate. 
As  to  this  last  character,  which  seems  the  best  of  the  lot,  pacifica 
(which  Bergh  treats  as  a variety  of  grcenlandica)  has  the  hooks  more 
strongly  denticulate  than  glaciolis  itself ! 

Bergh  says  Sars  confused  the  two  species.  Friele  [1901,  p.  68]  has 
not  hesitated  to  unite  them,  though  without  discussion.  Knipowitsch 
[1902,  pp.  361-363]  retains  them  nominally  separate,  though  conclud- 

a Kroyer’ s name  carnea  is  earlier  than  grcenlandica  but  is  a nomen  nudum  (see  remarks 
in  bibliography)  and  dates  only  from  Bergh’s  habilitation  of  it  in  1853.  This  is  also 
the  date  of  the  more  familiar  grcenlandica  Bergh,  which  luckily  may  be  retained  as 
having  page  priority. 


NO.  1761. 


A NEW  SPECIES  OF  ONCHIDIOPSIS — BALC1I 


477 


ing,  after  some  discussion  based  on  considerable  material  (all  from 
one  locality,  however),  that  groenlandica  is  at  most  a variety  of  gla- 
cialis.  He  did  not  have  pacifica  before  him.  He  found  that  four 
out  of  the  eight  specimens  which  he  separated  as  groenlandica  from  his 
single  specimen  of  glacialis  had  black  osphradia,  but  one  of  them  had 
also  denticulate  uncini. 

The  present  species  is  evidently  fully  congeneric,  but  is  much 
farther  from  any  of  the  above  forms  than  any  of  them  are  from  one 
another.  It  is  impossible  to  say  to  which  it  comes  nearest.  Like 
groenlandica , it  has  an  osphradium  with  black  base  and  nondenticulate 
inner  uncinal  hooks  in  the  radula.  In  the  median  tooth  (“rhachis” 
of  Bergh),  and  in  the  character  of  the  notseum,  it  is  nearer  glacialis . 
In  the  very  peculiar  penis  it  is  perhaps  nearest  pacifica.  But  in  the 
smooth  notseum  with  reticulate  pattern,  the  extraordinary  penis,  the 
shape  of  the  jaws,  the  shape  of  the  osphradium  leaflets,  and  above  all 
in  the  structure  of  the  shell,  it  is  sharply  distinguished  from  any  of 
them;  while  there  are  minor  points  of  individuality  in  the  radula, 
the  shape  and  musculature  of  the  rostrum,  the  form  of  the  tentacles 
and  proportion  of  the  eyes,  the  form  of  the  body  and  notseum  (espe- 
cially the  anterior  lappets),  and  the  shape  of  the  gill  leaflets. 

It  would  seem  that  the  species  of  the  genus  should  for  the  present 
be  written  as  follows: 

0.  glacialis  (Sars,  1850),  colorless  osphradium,  slightly  denticulate  uncinal  hooks, 
comparatively  smooth  notaeum,  gill  leaflets  not  auriculate  at  tip.  Distribution  paleo- 
boreal  and  arctic. 

0.  glacialis , var.  groenlandica  Bergh,  1853  (syn.:  carnea,  recondita,  reinhardti,  palliata ), 
osphradium  with  black  base,  nondenticulate  uncinal  hooks  (occasionally  denticulate), 
warty  notseum,  gill  leaflets  auriculate  at  tip.  Distribution  paleo-boreal  and  arctic.- 

0.  glacialis , var.  pacifica  Bergh,  1887,  osphradium  as  in  last,  uncinal  hooks  usually 
strongly  denticulate  (sometimes  smooth),  rhachis  peculiar,  penis  peculiar,  notseum 
as  in  last.  Distribution  pacifico-boreal. 

0.  corys , new  species,  osphradium  with  black  base  but  peculiar  form,  uncinal  hooks 
smooth  (in  the  unique  specimen),  notseum  (top)  smooth,  gill  leaflets  not  auriculate, 
penis  peculiar.  Distribution  neo-boreal  (?).  (Further  distinguished  from  the  glacialis 
forms  by  shell,  etc.,  as  elsewhere  stated.) 

THE  RELATIONSHIPS  OF  ONCHIDIOPSIS  TO  OTHER  GENERA  OF 

LAMELLARIIDflE.a 

The  Lamellariidse  constitute  a small,  highly  aberrant,  and  some- 
what heterogeneous  family,  treated  by  Bergh  as  distinct  from  the 
Velutinidse  and  containing  only  the  genera  Ghelynotush  (Swainson) 
Bergh,  Marsenia  Leach  [ = Lamellaria  Montagu],  Marseniella  Bergh, 
Marseniopsis  Bergh,  Marsenina  Gray,  and  Onchidiopsis  (Beck) 
Bergh.  The  Velutinidse,  however,  are  included  in  the  same  group 

a Called  by  Bergh  and  some  others  Marseniadse,  but  luckily  the  more  familiar  name 
Lamellaria  for  the  typical  genus  appears  to  be  correct  under  the  International  Rules, 
rather  than  Marsenia. 

b Better  treated  as  a subgenus  of  Lamellaria. 


478 


PROCEEDINGS  OF  THE  NATIONAL  MUSEUM. 


VOL.  08. 


by  Woodward  [1880],  Try  on  [1886],  Fischer  [1887],  Cooke  [1895], 
Simroth  [1896-1907],  and  most  other  systematists,  some  calling  the 
resulting  family  Lamellariidae,  some  Velutinidse. 

Bergh  himself  recognized  that  the  genera  Onchidiopsis  and  Mar- 
senina, at  least,  might' be  united  with  the  Yelutinidse  were  it  not  that  on 
the  other  hand  they  connect  through  the  puzzling  genus  Marseniopsis 
with  the  irreconcilable  genera  Chelynotus , Lamellaria,  and  Marseniella. 

Bergh  summarized  his  views  in  the  following: 


CONSPECTUS  GENERUM. 


Plica  expira- 
toria  nulla. 


[Armatura 

lingualis] 

1-1-1 


Plica  expira-  \ 
toria 


3-1-3 


Pars  inf.  vas  defer,  non 
libera Chelynotus  S\v. 

{Marsenia  Leach  [= 
Lamellaria ] 
Marseniella  Bergh 

[Test.  int.  calcarea Marseniopsis  Bergh 

Test,  semi-int.  calcarea. . Marsenina  Gray 
[Test.  int.  cornina Onchidiopsis  Bergh 


dioecious. 


>monoecious 


It  is  apparent  that,  but  for  the  contradictory  characters  of  Marseni- 
opsis, the  genera  would  fall  apart  in  two  well-marked  groups,  which 
may  be  called  the  Lamellaria  group  and  the  Onchidiopsis  group,  the 
latter  then  clearly  uniting  with  the  Yelutinidse,  which  agree  in  every 
essential  respect,  especially  dentition  and  hermaphroditism,®  except 
that  the  shell  is  still  external  and,  of  course,  the  expiratory  fold  is 
therefore  not  developed.6  In  short,  the  group  considered  as  a whole 
would  appear  as  either  monophyletic  but  sharply  divergent,  or  as 
di-phyletic  and  partially  convergent. 

The  introduction  of  Marseniopsis  into  the  scheme  makes  any 
orderly  phylogenetic  interpretation  impossible — that  is  to  say,  it 
makes  any  true  arrangement  impossible.  We  must,  therefore,  for 
any  conclusion,  await  new  facts,  particularly  as  to  Marseniopsis, 
which  it  would  be  desirable  to  investigate  further.  The  bearing  of 
the  new  species  which  is  the  subject  of  this  paper  on  the  situation  is, 
by  its  shell  structure,  to  draw  Onchidiopsis  closer  to  Marsenina,  par- 
tially bridging  the  gap  and  indicating  in  a most  interesting  way  the 
precise  manner  in  which  the  still  whorled  shell  of  Marsenina  has 
degenerated,  in  this  series,  to  the  mere  scale  of  the  other  species  of 
Onchidiopsis. 


aThe  hermaphroditism  of  Velutina  rests  on  the  bare  casual  mention  of  Bergh.  So 
interesting  a fact  should  be  verified.  The  preserved  material  at  my  command  has  not 
permitted  this.  There  is  reason  to  suspect,  as  Simroth  especially  has  suggested,  that 
hermaphroditism  among  the  prosobranchs  may  be  much  more  frequent  than  commonly 
supposed.  % 

b It  is  difficult  to  understand  the  high  morphological  significance  Bergh  appears  to 
attach  to  this  obviously  plastic  feature.  The  fold  is  in  fact  scarcely  so  much  an 
anatomical  character  as  an  habitual  manner  of  carrying  the  mantle  border.  The 
specimen  examined  by  me  suggests  the  idea  that  in  life  it  might  have  been  obliterated 
and  re-formed  at  will.  It  can  at  least  have  no  systematic  importance  in  a phylogenetic 
series  commencing  with  a shell-covered  form. 


no.  1761. 


A NEW  SPECIES  OF  ONCHIDIOPSIS—BALCH. 


479 


As  to  the  troublesome  Marseniopsis,  it  seems  closer  to  the  Velu- 
tininse  than  to  the  Lamellariinse.  The  extraordinary  aberrant  radula 
of  the  latter  is  a tangible  and  strong  point  of  demarcation  in  whicli 
no  error  of  observation  or  interpretation  is  likely.  It  is  an  unbridged 
gap,  and  Marseniopsis  is  here  wholly  with  the  Velutininse.  As  to 
the  two  characters  which  ally  it  with  the  Lamellariinse,  the  expiratory 
cleft  has  already  been  commented  on,  while  for  an  appreciation  of 
the  slight  and  almost  technical  character  of  the  line  separating 
androgyny  from  unisexuality  in  the  gasteropods  Pelseneer’s  paper 
should  be  consulted  (Pelseneer,  1894). 

Since  the  last  of  Bergh’s  writings  on  the  group  the  Australian 
genus  Caledoniella  Souverbie  1869,  hitherto  known  only  from  the 
shell,®  has  been  partially  elucidated  by  Basedow  [1905].  The  shell 
is  wholly  internal,  thin,  incompletely  calcified,  but  otherwise  not 
very  degenerate,  and  consists  of  3 + whorls.  It  is  strikingly  naticoid 
in  appearance.  The  radula  has  the  formula  2 — 1 — 1 — 1 — 2 and  in 
general  resembles  those  found  in  the  Velutinin8e — i.  e.,  is  naticoid. 
We  do  not  know  whether  the  animal  is  monoecious  or  dioecious.  Base- 
dow’s figures  do  not  show  any  expiratory  cleft  or  fold,  but  in  his 
generic  diagnosis  he  says: — “renal  aperture  on  the  right,  the  mantle- 
border  slightly  grooved  outward  from  this  spot,  ” which  may  indicate 
that  the  fold  is  present  in  rudimentary  form.  The  anatomical  data 
are  insufficient  for  placing  the  genus  with  entire  confidence,  but  so  far 
as  known  ally  it  with  Marsenina  and  Ouchidiopsis  in  the  Veiutininae, 
where  it  would  lie  near  the  base  of  the  series.  Two  things,  however, 
throw  doubt  on  the  correctness  of  this  disposition.  _ First,  if  Marsenina 
and  Ouchidiopsis  are  really  (as  believed)  derived  from  the  naticoids 
through  velutinoids,  then  it  is  difficult  to  see  how  Caledoniella  can  be 
introduced  into  the  series,  with  a shell  which,  though  more  degenerate- 
than  any  Velutina,  appears  to  relate  back  direct  to  Natica.  Second, 
Caledoniella  is  an  Australian  form,  thus  geographically  suggesting 
alliance  with  the  Lamellariinae,  which  though  world-wide  are  espe- 
cially tropical  and  austral,  rather  than  with  the  Velutininse,  which  are 
essentially  boreal.  It  may  be  suspected  that  if  all  the  facts  were 
known  Caledoniella  would  be  seen  to  be  a basal  term  of  the  Lamella- 
rioid  series,  its  apparently  greater  resemblance  to  the  Velutininse  being 
purely  negative  and  due  to  its  not  yet  having  acquired  the  peculiari- 
ties of  dentition  and  generative  system  which  mark  the  typical  Lamel- 
larioids.  This  implies  that  the  family  Lamellariidse  is  diphyletic, 
which  is  probably  the  case.  But  such  suspicions  can  not  be  allowed 
to  override  the  evidence  as  it  stands  and  Caledoniella  must  for  the 
present  rest  among  the  Yelutininae. 

The  group  considered  as  a whole  is,  at  all  events,  a most  interesting 
offshoot  from  the  naticoid  stem,  representing  evolution  in  the  same 

a The  animal  described  by  E.  A.  Smith  [1886]  as  Lamellaria  wilsoni  appears  to  have 
been  in  fact  a Caledoniella , but  the  description  is  not  sufficient  to  be  of  use. 


480 


PROCEEDINGS  OF  THE  NATIONAL  MUSEUM. 


vol.  38. 


direction  as  the  nudibranchs  among  opisthobranchs,  and  the  slugs 
among  pulmonates,  the  direction,  namely,  of  loss  of  shell.  This  loss 
apparently  proceeds  by  a kind  of  combination  of  the  methods  seen  in 
nudibranchs  and  slugs,  for  there  is  an  embryonic  “nautiloid”  shell 
afterward  shed  as  in  nudibranchs,  while  the  post-embryonic  shell  is 
overgrown  by  a notseum  and  degenerated  as  in  slugs.®  It  may  not 
be  wholly  a coincidence  that  the  group  has  developed  feeding  habits 
(on  compound  ascidians)  recalling  the  nudibranchs  and  has  become 
(at  least  in  part)  like  them,  hermaphroditic.  The  aberrant  character 
of  the  group  appears  in  the  well-known  and- extraordinary  “ nesting” 
habit  in  a hole  made  in  the  ascidian  colony  and  covered  with  an 
“ operculum.”  It  further  appears  in  the  sudden  radical  departure  of 
one  section  of  the  group  from  the  taenioglossate  type  of  dentition.6 

It  would  seem  that  the  best  provisional  treatment  of  the  family  is 
as  follows: 

Family  LAMELLARIIDiE  (various  family  characters  in  nervous 
system,  stomach,  etc.  Consult  Bergh). 

Subfamily  Lamellariin^e  (Radula  1-1-1,  of  aberrant  form. 
Sexes  separate.  Shell  few  whorled,  wholly  internal,  but  calcareous 
though  sometimes  very  degenerate.0  No  expiratory  cleft.  Nearly 
world- wide  but  especially  tropical). 

Genus  Lamellaria  Montagu  (part),  1815  (syn.  includes  Coriocella 
Blainville,  1824,  Cryptothyra  Menke,  1830,  Marsenia  Leach,  1847, 
Cryptocella  H.  and  A.  Adams,  1853 , Ermea  Gray,  1857). 

Subgenus  Marseniella  Bergh. 

Subgenus  Chelynotus  (Swainson,  1849)  Bergh. 

Subfamily  Velutinin^e.  (Radula  2— 1—1— 1—2,  of  naticoid  form. 
Sexes  united.  Shell  progressively  degenerating  from  several  whorled, 
external,  calcareous  though  thin,  to  a mere  internal  horny  scale. 
Expiratory  cleft  developed  where  shell  is  internal.  Boreal  except 
Caledoniella.) 

a May  it  be  that  the  spicules  of  the  dorid  nudibranchs  represent  an  exactly  similar 
phenomenon?  It  has  been  generally  assumed  that  the  loss  of  the  nautiloid  embryonic- 
shell  ends  the  shell-history  of  the  individual  dorid  and  that  the  spicules  with  which 
the  notaeum  is  so  plentifully  beset  represent  a novel  formation.  The  same  assump- 
tion might  have  been  made  for  Onchidiopsis  were  not  the  shell,  especially  in  the  species 
here  described,  still  unmistakable  as  such.  In  other  words,  if  we  use  the  history  of 
the  shell  in  Onchidiopsis , which  is  still  decipherable,  as  a key  to  read  the  history  of 
the  shell  in  the  dorids,  where  it  is  not  clearly  decipherable,  we  shall  conclude  that 
the  lost  “nautiloid”  shell  is  only  the  protoconch  and  shall  homologize  the  spicules 
of  the  adult  note um  with  the  adult  internal  shell  of  Onchidiopsis.  There  is  nothing 
in  the  morphological  relations  of  the  noteum  and  mantle  to  forbid  this,  and  it  seems 
to  the  writer  worthy  of  serious  consideration. 

b The  strikingly  parallel  aberration  of  the  subgenus  Turritellopsis,  in  the  Turritel- 
lidse,  should  be  compared,  however,  as  an  illustration  of  how  profoundly  and  suddenly 
the  tenioglossate  type  of  dentition  may  be  modified  without  any  apparent  great  change 
in  the  rest  of  the  organism.  Figures  may  be  found  in  Tryon’s  Manual. 

c “Presque  membraneuse.”  L.  leptolemma  Bergh. 


no.  1761. 


A NEW  SPECIES  OF  ONCHIDIOPSIS—BALCH. 


481 


Genus  Velutina  Fleming  1822. 

Subgenus  Limneria  H.  and  A.  Adams,  1853  (syn.  Mcrvillia 
Gray  1857). 

Subgenus  Velutella  Gray,  1847. 

Genus  Caledoniella  Souverbie,  1869. 

Genus  Marsenina,  Gray,  1850. 

Genus  Onchidiopsis  (Beck)  Bergh,  1853. 

GENERA  OP  UNCERTAIN  POSITION. 

Genus  Marseniopsis  Bergh,  1886.  Radula  2— 1—1— 1—2.  Shell 
internal,  calcareous,  degenerate.  Sexes  separate.  Strictly  austral. 

Genus  Lamellariopsis  Vayssiere  [1906].  Radula  2-1-1-1-2. 
Shell  internal,  calcareous,  thin,  paucispiral.  The  published  “ diag- 
nosis” (quite  insufficient)  does  not  show  any  generic  difference  from 
Marsenina.  Austral. 

Genera  Leptonotis,  Gray,  1847 ; Scsevogyra,  Whitfield,  1877 ; Lyo- 
soma,  White,  1883.  Fossil. 

[In  addition  numerous  names  applied  to  the  embryonic  shells — 
see  Tryon  and  Bergh.] 

LITERATURE. 

Basedow,  Herbert. 

[1905.]  On  Naticoid  Genera  Lamellaria  and  Caledoniella  from  South  Australia. 
Trans.  Royal  Soc.  South  Australia,  vol.  29,  1905,  pp.  181-186,  pis.  26-29. 
Bateson,  William. 

[1894.]  Materials  for  the  Study  of  Variation  treated  with  especial  regard  to  Dis- 
• continuity  in  the  Origin  of  Species.  Macmillan  & Co.,  1894. 

Bergh,  Rudolph. 

[1853.]  Bidrag  til  en  Monographi  af  Marseniaderne,  en  Familie  af  de  gastrseopode 
Mollusker.  En  critisk,  zootomisk,  zoologisk  Undersogelse.  Kongl.  Danske 
Vid.  Selsk.  Skrift,  5te  Raekke,  naturvid.  og  math.  Afd.,  3die  Bind,  1853,  pp. 
239-350,  pis.  1-5. 

Although  since  corrected  and  amplified  in  many  respects  by  the  later 
researches  of  the  author,  this  work  of  his  youth  remains  the  indispensable 
storehouse  of  original  observations  on  the  Lamellariidse,  and  the  basis  of  our 
modern  classification.  Unfortunately  the  plates  are  poor  and  the  text  in 
Danish  only.  There  is  a “separate”  issue  repaged  1-119.  Pages  cited  in 
text  are  from  original  pagination. 

[1857.]  Bidrag  til  en  anatomisk  Undersogelse  af  Marsenina  prodita  (Loven). 

Naturh.  For.  Vid.  Medd.,  Kjobenhavn,  1857,  pp.  1-15,  pi.  1. 

[1885.]  Die  Marseniaden.  Zoologischen  Jahrbtichern,  vol.  1,  1885,  pp.  165-176, 
1 text-fig. 

This  short  but  valuable  paper  was  an  early  announcement  of  the  author’s 
chief  generalizations  from  the  Challenger  material  and  the  material  from 
Semper’s  Philippine  journeys.  It  need  not,  however,  be  consulted  by  the 
English  student,  as  a translation  has  been  published  practically  unchanged 
in  the  Challenger  reports.  See  next  item. 

[1886.]  Report  on  the  Marseniadse.  Voy.  Challenger , Zool.,  vol.  15,  pt.  41, 
1886,  pp.  1-24,  pi.  1. 

The  first,  or  general  part,  appears  to  be  a nearly,  if  not  quite,  literal  trans- 
lation of  the  item  last  above.  It  will  be  found  the  most  satisfactory  and  acces- 
sible brief  general  account  for  most  English  readers. 

Proc.N.M.vol.38— 10 31 


482 


PROCEEDINGS  OE  THE  NATIONAL  MUSEUM. 


vol.  38. 


Bergh,  Rudolph — Continued. 

[1886-87.]  Die  Marseniaden.  MalacologischeUntersuchungen  (in  Semper’s  Reisen 
nach.  Philipp.,  vol.  2,  ii),  Supplement,  hefte3  and  4,  1886-87,  pis.  1-11. 

A great  monograph  of  the  whole  family,  summing  up  and  supplementing 
the  author’s  whole  previous  work  thereon,  and  practically  his  last  word  on 
the  subject — unfortunately,  however,  not  representative  of  his  best  work. 
The  same  matter  as  in  the  last  two  items  once  more  appears  nearly  unchanged, 
but  forming  only  a small  part  of  the  whole  monograph. 

[1893.]  Opisthobranches  provenant  des  Campagnes  du  Yacht  V Hirondelle.  Resul- 
tats  des  Campagnes  scientifiques  accomplies  sur  son  yacht,  par  Albert  ler 
Prince  Souverain  de  Monaco,  publies  sous  sa  Direction  avec  le  concours  du 
Baron  Jules  de  Guerne  charge  des  Travaux  Zoologiques  a bord.  Fascic.  4, 
1893,  pp.  30-32. 

[1898.]  Die  Opisthobranchien  der  Sammlung  Plate,  Zoologischen  Jahrbuchern, 
Supplement  4,  heft  3,  1898  (Anhang,  pp.  562-573,  pis.  32-33). 

[1899.]  Nudibranches  et  Marsenia  provenant  des  Campagnes  de  la  Princess- Alice 
(1891-1897).  Resultats  des  Campagnes  scientifiques  accomplies  sur  son 
yacht,  par  Albert  ler,  Prince  Souverain  de  Monaco,  publies  sous  sa  direction 
avec  le  concours  de  M.  Jules  Richard,  Doct.  es-sciences,  charge  des 
Travaux  Zoologiques  a bord,  fascic.  14,  1899,  pp.  30-39,  pis.  1,  2. 

Cooke,  Rev.  A.  H. 

[1895.]  Molluscs  (The  Cambridge  Natural  History,  vol.  3),  pp.  1-459,  Macmillan 
& Co.,  1895. 

Fischer,  Paul. 

[1881-1887.]  Manuel  de  Conchyliologie  et  de  Paleontologie  conchyliologique, 
ou  Histoire  naturelledes  Mollusques  vivantset  fossiles.  Paris,  1881-1887. 

Friele,  Herman. 

[1901.]  Den  Norske  Nordhavs-Expedition,  1876-1878,  vol.  28,  Zoologi,  Mollusca, 
3,  pp.  i-viii,  1-129,  list  of  stations  and  map.  Fol.,  Christiania,  1901. 

Knipowitsch,  N. 

[1902.]  Zoologische  Ergebnisse  der  Russischen  Expeditionen  nach  Spitzbergen. 
Mollusca  and  Brachiopoda  2 and  3.  Ann.  Mus.  Zool.  St.  Petersberg,  vol.  7, 
1902,  pp.  355-459,  pis.  8-9. 

Kroyer,  Dr.  H. 

[1847.]  Yerzeichniss  der  Naturaliensammlung,  welche  auf  Befehl  des  Konigs 
aus  verschiedenen  Koniglichen  Musaen  in  Kopenhagen,  so  wie  auch  aus 
einigen  Privatsammlungen  zur  24.  Yersammlung  Deutscher  Naturforscher 
und  Aerzte  nach  Kiel  gesandt  war.  2.  Weichthiere  aus  der  Sammlung  der 
Herrn  Dr.  Kroyer.  a.  Von  Spitzbergen.  b.  Von  Norwegen  und  Danemark. 
In:  Amtlicher  Bericht  ueber  die  24.  Versammlung  Deutscher  Naturforscher 
und  Aerzte  in  Kiel  in  September,  1846.  Kiel,  1847. 

In  the  list  of  mollusca  from  Kroyer’s  collection,  which  begins  on  p.  115, 
the  species  are  numbered,  and  on  that  page,  under  the  caption  “a.  Von 
Spitzbergen,”  Nos.  10  and  11  are  respectively  u Coriocella  cornea  Kr. — 1 
(exemplar)”  and  “ Coriocella  recondita  Kr. — 1 ditto.”  They  are  absolutely 
nomina  nuda,  and  could  only  date  from  their  habilitation  by  Bergh  in  1853. 

Morch,  O.  A.  L. 

[1868.]  Faunula  Molluscorum  Islandiae.  (Oversigt  over  Islands  Bloddyr.) 
Yidenskab.  Meddelelser  fra  den  naturhistoriske  Forening  i Kjobenhavn  for 
Aaret  1868,  nos.  11-13,  pp.  185-229.  Copenhagen,  1869. 

The  entire  volume  bears  date  1869  but  apparently  the  numbers  originally 
issued  separately,  and  this  article  appeared  in  1868. 

Pelseneer,  Paul. 

[1894.]  Hermaphroditism  in  Mollusca.  Quart.  Journ.  Micr.  Sci.,  vol.  37,  1894, 
pp.  19-46,  pis.  4-6. 


no.  1761 


A NEW  SPECIES  OF  ONCHIDIOPSIS— BALC 11 


483 


POSSELT,  HENR.  J. 

[1898.]  Gronlands  Brachiopoder  og  Bloddyr.  In:  Meddelelser  om  Gronland, 
udg.  Comm.  Ledelsen  geol.  og.  geogr.  Undersogelser  i Gronland.  Heft 
XXIII,  Afd.  i,  vol.  1,  1898,  pp.  i-xix,  1-298,  pis.  1-2,  Kjobenhavn,  1898,  8V°. 

Often  cited  as  “Conspectus  Faunae  Groenlandicae,”  a subtitle  which  seems 
to  have  been  added  in  the  “separate”  issue. 

Sars,  G.  O. 

[1878.]  Mollusca  Regionis  Arcticae  Norvegiae.  Bidrag  til  Kundskaben  om 
Norges  Arktiske  Fauna,  vol.  1,  pp.  i-xv,  1-466,  pis.  1-34  (shells  and  animals) 
and  1-18  (dentition  and  opercula),  Christiania,  1878. 

Sars,  M. 

[1850.]  Beretning  om  en  i Sommeren  1849  foretagen  zoologisk  Reise  i Lofoten  og 
Finmarken.  Nyt  Magazin  for  Naturvidensk.,  vol.  6,  heft  2,  1850,  pp.  121-211. 

Simroth,  Dr.  H. 

[1896-1907.]  Bronn’s  Klass.  u.  Ord.  des  Tier-Reichs,  vol.  3,  Mollusca,  2er  Ab- 
teilung,  Gastropoda  prosobranchia,  pp.  i-vii,  1-1056,  pis.  1-63,  Leipzig. 
Issued  in  separate  Lieferungen  from  1896  to  1907. 

Smith,  Edgar  A. 

[1886.]  Description  of  a new  species  of  Lamellaria from  South  Australia.  Ann. 
and  Mag.  Nat.  Hist.,  ser.  5,  vol.  18,  1886,  pp.  270-275,  1 text-fig. 

Tryon,  Geo.  W.,  Jr. 

[1886.]  Manual  of  Conchology;  structural  and  systematic,  vol.  8.  Naticidse 
(etc.),  Philadelphia,  1886. 

Vayssiere,  A. 

[1906a.]  Diagnoses  generiques  de  Mollusques  Gasteropodes  nouveaux  rapportes 
par  l’Expedition  antarctique  du  Dr.  Charcot.  Bull.  Mus.  Hist.  Nat.  Paris, 
1906,  pp.  147-149. 

[19066.]  Sur  les  Gasteropodes  Nudibranches  et  sur  les  Marseniades  de  P Expe- 
dition antarctique  du  Dr.  Charcot.  Compt.  Rend.  Acad.  Sci.  Paris,  vol.  142, 
1906,  pp.  718-719. 

Woodward,  ’S.  P. 

[1880.]  A Manual  of  the  Mollusca,  being  a treatise  on  recent  and  fossil  shells. 
4th  ed.,  London,  1880. 

DESCRIPTION  OF  PLATES. 

Plate  21. 

Fig.  1.  Onchidiopsis  corps.  Dorsal  view;  6.=eye;  ex.  cZ.=expiratory  cleft;  in.  cl.— 
inspiratory  cleft;  l.  Z.=left  lobe  of  anterior  lappet;  l.  L=left  tentacle;  r.= 
rostrum;  r.  £.=right  lobe  of  anterior  lappet. 

2.  Onchidiopsis  corps.  Ventral  view.  Lettering  as  in  fig.  1 ; also:  ah.  e.=abnormal 

eye;  m.=  mouth;  m.  c.= man  tie  cavity. 

3.  Onchidiopsis  corps.  View  from  right  side.  Lettering  as  in  figs.  1 and  2;  also: 

p.=penis;  r.  L=right  tentacle. 

4.  Onchidiopsis  corps.  Shell.  View  from  right  side  and  looking  slightly  from 

rear  and  above.  The  infolded  posterior  portion  is  seen  through  the  anterior 
portion.  A.=anterior;  Z).=dorsal;  P.=posterior;  F.=ventral.  (In  this 
and  next  two  figures  the  shell  appears  too  solid,  being  in  reality  a nearly 
colorless  translucent  film.) 

5.  Onchidiopsis  corps.  Shell.  View  from  right  side  and  looking  from  rear  and 

below.  L.—  left;  P.=right.  Remarks  as  in  last. 

6.  Onchidiopsis  corps.  Shell.  View  from  below.  Lettering  and  remarks  as  in 

figs.  4 and  5.  (The  waving  of  the  infolded  portion  appears  exaggerated  in 
this  figure.) 


484 


PROCEEDING, S'  OF  THE  NATIONAL  MUSEUM . 


vol.  38. 


Fig.  7.  Marsenina  prodita.  Shell.  (This  and  next  two  figures  are  drawn,  regardless 
of  scale,  for  comparison  of  shell  structure,  forming  a progressive  degenera- 
tion series.) 

8.  Marsenina  ampla.  Shell.  See  remarks  under  fig.  7. 

9.  Onchidiopsis  corps.  Shell,  represented  semidiagrammatically  as  a solid  object, 

from  below.  See  remarks  under  fig.  7. 

10.  Onchidiopsis  corps.  Osphradium  and  ctenidium,  semidiagrammatically  rep- 
resented from  an  anterior  viewpoint.  Ct . =ctenidium ; D.  =dorsal ; L. =left; 
Os.  =osphradium;  P.=right;  V.= ventral.  The  stippling  represents  the 
black-pigmented  areas  on  the  roof  of  the  gill  cavity  and  basal  surfaces  of 
the  lobes  of  the  osphradial  leaflets. 

Plate  22. 

Fig.  1.  Onchidiopsis  corps.  Dorsal  view  of  head  region.  Notseum  is  slightly  slit  up 
from  inspiratory  cleft  and  the  lobes  of  the  anterior  lappet  turned  back. 
ah.  e.=abnormal  eye;  ah.  £.=abnormal  (external)  branch  of  the  bifid  left 
tentacle;  6.=foot;  e. = eye ;/.= auricle  of  foot;  g.  c.=opening  of  gill  cavity ; 

l.  Z.=left  lobe  of  anterior  lappet;  l.  L=left  tentacle;  p.  has.=  penis,  basal 
portion;  p.  cr.=penis,  crest;  r.=  rostrum;  r.  /.=right  lobe  of  anterior  lappet; 
r.  £.=right  tentacle. 

2.  Dissection  of  rostrum.  Dorsal  view.  6.  ra.=buccal  mass;  ^.=jaws;  l.  t.—\eit 

tentacle;  ph.= wall  of  pharynx;  ph.  cav.= pharyngeal  cavity;  r.=jostrum; 
rac?.=radula;  rad.  sac. =radula  sac;  re.  m .=retractor  muscles;  r.£.=right 
tentacle.  (The  walls  of  the  dorsal  half  of  the  rostrum  are  represented 
as  cleanly  cut  away  except  at  the  tip,  which  is  intact.  The  retractor 
muscle  bundles,  which  line  it,  are  only  partially  shown,  and  some  are 
represented  as  broken  and  pushed  aside  to  allow  a view  of- the  pharynx. 
The  thin-walled  pharynx  is  represented  as  partially  transparent,  and 
through  it,  represented  in  dotted  lines,  are  seen  the  jaws  and  the  buccal 
mass,  the  latter  containing  the  greater  portion  of  the  radula.  On  top  of  the 
pharynx  and  to  the  left  lies  the  radula  sac,  a prolongation  of  the  buccal 
mass  the  neck  of  which  pierces  the  pharynx  wall.  The  radula  is  shown 
as  if  the  radula  sac  and  buccal  mass  were  semitransparent.) 

3.  Semidiagram ma tic  view  of  rostrum  from  left  side.  The  wall  of  the  rostrum 

is  supposed  to  be  wholly  removed  except  at  the  tip,  where  it  is  intact.  As 
in  the  last  figure,  the  jaws  and  buccal  mass  are  represented  as  seen  through 
the  thin- walled  pharynx,  and  the  radula  as  if  seen  inside  the  buccal 
mass  and  radula  sac;  but  in  this  figure  their  lines  are  not  dotted.  Lettering 
as  in  last;  also,  ra.=mouth. 

4.  Jaws,  seen  from  left  side.  M.=anterior;  Z>.=dorsal;  P.=posterior;  F.=ven- 

tral. 

5.  Radula.  Dorsal  view  of  three  rows  from  near  broadest  point  (about  ten  rows 

from  anterior  end).  Camera  lucida  drawing.  X oc.  1,  obj.  3. 

0.  Radula.  Two  uncinal  hooks  from  right  side.  Camera  lucida  drawing. 
X oc.  1,  obj.  7. 


Plate  .21,  figures  1,  2,  3,  and  10,  and  Plate  22,  all  figures,  were  drawn  by  the  author 
from  the  specimen.  Plate  21,  figures  4,  5,  and  6,  were,  drawn  by  Mr.  Sergius  Morgulis, 
from  the  specimen.  Plate  21,  figures  7 and  8,  are  copied  from  figures  reproduced  in 
Tryon’s  Manual  of  Conchology. 


U.  S.  NATIONAL  MUSEUM 


PROCEEDINGS,  VOL.  38  PL.  21 


A New  Labradorean  Species  of  Onchidiopsis. 

For  explanation  of  plate  see  page  483. 


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Of  THE. 

UNIVERSITY  Of  ILLINOIS 


U.  S.  NATIONAL  MUSEUM 


PROCEEDINGS,  VOL.  38  PL.  22 


A New  Labradorean  Species  of  Onchidiopsis. 

For  explanation  of  plate  see  pages  483  and  484. 


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